Apparatus and Method for Inspecting Laminated Structure

Abstract

Disclosed is an apparatus, method and system for inspecting structures, and more particularly for evaluating the condition of a structure. The disclosed nondestructive inspection testing method and apparatus enables an operator to assess the condition of a structure, such as a composite laminate part and determining the location and depth of anomalies. The method includes generating a subsurface longitudinal ultrasonic wave signal at a high incidence angle into a structure being evaluated and collecting at least one of any front, back or side reflected wave data. The method may include processing the reflected wave data to determine the condition of the structure, including any anomalies that may have been detected and their location, size and shape.

Description

TECHNICAL FIELD[0001]The present disclosure relates generally to the inspection of structures such as composite fiber reinforced plastic (CFRP) used in aircraft or other structures, and more particularly to methods, apparatuses and systems for assessing the condition of a laminated structure.BACKGROUND[0002]Lightweight composite materials are being used more extensively in the aerospace industry for both commercial and military aircraft and other aerospace vehicles, as well as in other industries. The structures using these composite materials may be formed using multiple plies or layers of material that may be laminated together to form high strength structure. These structures may undergo further machining processes during manufacturing and assembly of vehicles (drilling, cutting, countersinking, shimming, fastener removal, etc.); as well as further processes related to flight and ground operations (maintenance, repair, retrofit, or overhaul); and damages from an impact or other c...

AI Technical Summary

Benefits of technology

[0008]It is an object of the present disclosure to eliminate or reduce the above described disadvantages. The following embodiments and aspects t

Problems solved by technology

Conventional pulse echo ultrasound is often reflected by the first delamination, and as a result it limits the operator from acquiring data on the delamination lying beneath it in a stratum of plies.

Another difficulty is that conventional transducers with sufficient energy and appropriately narrow beam spread, are physically too large to be incorporated in a transducer wedge that can be inserted in a small hole for inspection of the structure open to the hole.

A further disadvantage of existing solutions is that the maximum depth of the damage is unknown without repeated cycles of inspecting and sanding which results in removal of overlying material.

Since repairs often require a 30:1 taper on the sanded-out crater or “scarf”; small damage that is only a few plies deep can result in a large repair surface area that intrudes on other structures, and requires major disassembly.

Large repairs also may result in a large area exposed to heat when the repair plies are cured.

Further, the time spent in repeated cycles of inspection and sanding to establish the eventual repair size can be considerable.

Often, intermediate inspections reveal damage that was not discernible prior to the start of damage removal operations.

Current methods do not allow inspectors to characterize the condition in “one shot process”, and thereby hampers early development of a plan that encompasses the magnitude of the subsequent repair.

Visual and remote visual inspection methods are also used to try to image delamination in damaged areas and drilled holes, but experience has shown that some delamination are missed by visual inspection, while being detected by ultrasonics.

This may be due to tightness of the delamination, glare conditions in the hole, or drilling dust filling the delamination surface.

Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

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